Danica Patrick had a vastly different opening weekend at Daytona this year than she did in 2013. / Jasen Vinlove, USA TODAY Sports

by Jeff Gluck, USA TODAY Sports

by Jeff Gluck, USA TODAY Sports

DAYTONA BEACH, Fla. - NASCAR's two main Chevrolet engine programs had wildly different days on Saturday.

While Earnhardt-Childress Racing engines powered their drivers to the top spots in both Daytona 500 practice sessions on a sunny afternoon at Daytona International Speedway, Hendrick Motorsports engines struggled with three failures. The practices were the last chance to get cars set up before Sunday's Daytona 500 qualifying.

The fastest two drivers in both practices were part of Richard Childress Racing - Paul Menard and Ryan Newman in the first session and Newman and Austin Dillon in the second.

Last year, Daytona 500 pole-sitter Danica Patrick was third in the first session and led the second one.

But Saturday was drastically different for Patrick and two other Hendrick-powered drivers. She suffered a blown engine, along with Stewart-Haas Racing teammate Tony Stewart and HScott Motorsports' Bobby Labonte.

"It's very different than last time," said Patrick who was no better than 19th in either session. "I don't doubt everybody and their effort and ability to fix it. The bright side is it didn't happen in qualifying, it happened before."

Patrick said she was less than five seconds from shutting off her engine, which might have left the motor as a ticking time bomb for Sunday afternoon.

If Patrick, Stewart or Labonte win the pole position on Sunday, they'll be the pole-sitter in name only. NASCAR said all three drivers will start in the rear of the field for both Thursday's Budweiser Duels and the Daytona 500.

"It happens like that," Patrick crew chief Tony Gibson said of the spate of failures. "Several times, you'll see two or three of them blow up at the same time. In qualifying trim, you're asking these things to do a lot, man. We'll work it out."

Scott Maxim, Hendrick's director of track engine support, said driver comments and preliminary data suggested something had failed in the bottom end of the power curve. But until taking the engines apart for a closer look, he said, the engine specialists couldn't be sure what went wrong.

"We'll identify what we've got and make changes if needed," he said. "We think we'll be able to make corrective action. Certainly for (Sunday's qualifying), we'll be able to look the engines over closely and make sure we're not going into (Sunday) with an issue. Then after that, we'll be all good."

Steve Addington, HScott's competition director, said he was confident Hendrick would come up with answers.

"Something went wrong in the bottom end," he said. "They're going to change that. They're going to look at that, and I'm sure they'll look close at the others."